Extension of Tribute Mining Agreement Longstop date

December 12, 2017

Extension of Tribute Mining Agreement Longstop date

12 December 2017

AIM: STEL

Stellar Diamonds plc

(“Stellar” or the “Company”)

Extension of Tribute Mining Agreement Longstop date

Stellar Diamonds plc, the London listed diamond development company focused on West Africa, announces that it has agreed with Octea Mining to extend the longstop date (for the satisfaction of certain of the conditions precedent of the binding Tribute Mining and Revenue Agreements ( “Agreements”) in relation to the Tongo-Tonguma mine development project in Sierra Leone, as defined in the announcement dated 28 April 2017) to 31 January 2018 whilst certain project funding options are being pursued. Stellar will undertake to cover project costs at Tonguma during the longstop period, which equate to approximately US$80,000 per month. Tonguma is a 25 year mining licence that is located adjacent to Stellar’s Tongo licence, which together form the Tongo-Tonguma project that hosts the 4.5 million carat resource currently defined from three individual high grade kimberlites that stretch across the licences. Tonguma hosts significant camp facilities and other infrastructure which will be used as the platform for the future mine development and kimberlite ore processing, thus saving significant time and money in the lead up to the proposed mine development.

Stellar is an AIM listed (AIM: STEL) diamond development company focused on the 4.5 million carat high-grade and high value Tongo-Tonguma kimberlite diamond project in the world famous diamond fields of eastern Sierra Leone. An independently generated mine plan, based on over 66,000m of drilling that has been completed to date, envisages the production of over 4 million carats, generating gross revenues of more than US$1.2 billion, over a 21 year life of mine. Initial production at Tongo-Tonguma is scheduled to occur in the first year of development, building up to over 200,000 carats per annum, with a weighted average modelled diamond value of $229 per carat. The Tongo-Tonguma mine is estimated to give Stellar an attributable a Post-tax NPV(8) of US$109 million and IRR of 31%.

This announcement contains inside information for the purposes of Article 7 of EU Regulation 596/2014.

Caution regarding forward looking statements

Certain statements in this announcement, are, or may be deemed to be, forward looking statements. Forward looking statements are identiﬁed by their use of terms and phrases such as ”believe”, ”could”, “should” ”envisage”, ”estimate”, ”intend”, ”may”, ”plan”, ”potentially”, ”will” or the negative of those, variations or comparable expressions, including references to assumptions. These forward looking statements are not based on historical facts but rather on the Directors’ current expectations and assumptions regarding the Company’s future growth, results of operations, performance, future capital and other expenditures (including the amount, nature and sources of funding thereof), competitive advantages, business prospects and opportunities. In particular, there is no guarantee that the Company will be able to complete the Tribute Mining Agreement. Such forward looking statements reﬂect the Directors’ current beliefs and assumptions and are based on information currently available to the Directors.

A number of factors could cause actual results to differ materially from the results discussed in the forward looking statements including risks associated with vulnerability to general economic and business conditions, competition, environmental and other regulatory changes, actions by governmental authorities, the availability of capital markets, reliance on key personnel, uninsured and underinsured losses and other factors, many of which are beyond the control of the Company. Although any forward looking statements contained in this announcement are based upon what the Directors believe to be reasonable assumptions, the Company cannot assure investors that actual results will be consistent with such forward looking statements. Accordingly, readers are cautioned not to place undue reliance on forward looking statements. Subject to any continuing obligations under applicable law or any relevant AIM Rule requirements, in providing this information the Company does not undertake any obligation to publicly update or revise any of the forward looking statements or to advise of any change in events, conditions or circumstances on which any such statement is based.